Prelimisnary findings on the use of intravascular ultrasound in the assessment of pediatric pulmonary vein stenosis
Callahan R, Jenkins KJ, Gauthier Z, Gauvreau K, Porras D.
Catheter Cardiovasc Interv. 2020 Sep 16. doi: 10.1002/ccd.29264. Online ahead of print.
Take Home Points:
- Intravascular ultrasound (IVUS) was able to be safely performed in patients undergoing catheterization for assessment of pulmonary vein stenosis.
- IVUS allowed for better characterization of pulmonary vein pathology with moderate inter-observer reproducibility.
Commentary from Dr. Konstantin Averin (Edmonton), catheterization section editor of Pediatric Cardiology Journal Watch: The etiology of pulmonary vein stenosis (PVS) in the pediatric population is heterogeneous and can be challenging to delineate via traditional angiography. Intravascular ultrasound (IVUS) is additive in the assessment of adult venous pathology. The use of IVUS in pediatric patients with PVS has not been previously reported. The authors sought to describe their retrospective single center experience using IVUS in the assessment of pediatric patients with PVS.
From August 1, 2016 to December 31, 2019 IVUS was performed in 81 pulmonary veins during 54 catheterizations in 50 patients (median age 1.7 yrs. [0.9-3.1], median weight 8.6 kgs [7.3, 11.8]). Angiography and IVUS images were reviewed by 2 independent observers and IVUS images were categorized according to the schema below (Figure 1) – initially as adequately or inadequately imaged and then according to the presence of presumed intimal thickening (PIT). Most pulmonary veins (88%) were adequately imaged, and the inadequately imaged veins were early in the centers experience. About 50% had PIT, with the obstruction in the remaining veins being related to ostial stenosis or compression/distortion. The authors provide several nice examples of IVUS imaging of the different pulmonary vein categories (Figure 2). There was no obvious increase in adverse events during procedures where IVUS was used. IVUS classifications were moderately reproducible – in patients with existing stents there was 100 inter-rater agreement with regard to presence or absence of in-stent stenosis, while in patients without stents there was somewhat less inter-rater reliability with a combined precent agreement of 75% and a k of 0.67.
The authors nicely demonstrate that IVUS can be safely performed in this novel pediatric population. However, as the authors acknowledge, this paper raises many more questions than it answers. Further work should focus on whether this imaging modality will allow precise definition of pulmonary vein pathology, assist in tailoring treatment, and improve patient outcomes. Given the complexity and high morbidity of pediatric PVS stenosis IVUS may play an important role in improving outcomes of this disease.
Figure 2. Intravascular ultrasound of pulmonary veins contrasted with pulmonary vein pathology specimens (all four examples obtained from different patients); (a) IVUS image of normal pulmonary vein with a thin wall and circular lumen, (b) circumferential specimen of a normal pulmonary vein, (c) IVUS image of vein with presumed intimal thickening and luminal narrowing, (d) circumferential specimen of pulmonary vein with intraluminal pulmonary vein stenosis (neo-intimal proliferation).